Power supply circuit and power supply apparatus

A power supply circuit comprising:

• a first P-channel MOSFET provided between an on-board power supply and a vehicular apparatus that is a power supply target, and configured to switch between a power-ON state in which electric power is supplied to the vehicular apparatus and a power-OFF state in which the supply of the electric power is interrupted;
• a first voltage application circuit;
• a first contact on a first connection line connecting the first P-channel MOSFET and the on-board power supply, the first contact being connected to the first voltage application circuit, and the first voltage application circuit being connected between the first contact and the first P-channel MOSFET, wherein
• a source terminal of the first P-channel MOSFET is connected to the first contact and the on-board power supply, and
• the first voltage application circuit is configured to:
• apply a voltage having a potential lower than a potential of the on-board power supply to a gate terminal of the first P-channel MOSFET such that a state of the first P-channel MOSFET is switched to the power-ON state;
• and
• apply a voltage having a potential equal to the potential of the on-board power supply to the gate terminal of the first P-channel MOSFET such that the state of the first P-channel MOSFET is switched to the power-OFF state;
• a second P-channel MOSFET provided between the first P-channel MOSFET and the vehicular apparatus, wherein
• the first P-channel MOSFET and the second P-channel MOSFET are connected in series by connecting a drain terminal of the first P-channel MOSFET to a drain terminal of the second P-channel MOSFET,
• a source terminal of the second P-channel MOSFET is connected to the vehicular apparatus,
• the first voltage application circuit comprises a switching circuit,
• the switching circuit of the first voltage application circuit comprises:
• a first NPN bipolar transistor;
• and
• a first PNP bipolar transistor;
• the first NPN bipolar transistor is connected to the on-board power supply via a collector terminal of the first NPN bipolar transistor and the first contact, and
• the first PNP bipolar transistor is connected to the on-board power supply via an emitter terminal of the first PNP bipolar transistor and the first contact, and is connected to the first P-channel MOSFET via a collector terminal of the first PNP bipolar transistor and the gate terminal of the first P-channel MOSFET.